Open file formats and interoperability have nothing to do with supporting half baked DRM schemes. Adobe is only there to entrench it's own technology. Though I'll give them this. PDF is an ISO standard(since 2008). DRM is not a solution it's part of the problem.

This not just about DRM. Amazon decided to implement the Adobe SDK. This alone is huge, considering that until now Amazon's own format, Mobi, was the one and only format they believed in. And while the DX does not implement all the features of the SDK yet (e.g. ePub + Content Server), it's not a long shot to assume that one day it might.

You may not like DRM, but let's face it - without DRM, publishers, at their current limited state of mind, would be even less helpful in supporting the e-book movement.